The present invention relates to a modular converter unit, and to a power converter assembly which includes at least one modular converter unit.
British Pat. No. GB 2 178 243 A describes a compact power assembly, consisting of two power units. Each power units has several branch pair modules which are mounted on a support plate of a cooling unit. The two power units are arranged on opposite sides of the compact power assembly and combined with their respective cooling units so as to eliminate gaps between the cooling units and the assembled support plate. The assembly is held together with two plates. This compact power assembly also includes a fan unit which is connected by a cooling air channel with the intake side of the two cooling units of the compact power assembly. The branch modules of each power unit are electrically connected with each other by a printed circuit board that includes control and/or protection devices. The terminals of the branch modules of each power unit are distributed on the printed circuit board in such a way that the AC-terminals are located on one side, while the DC-terminals are located on the opposite side. The DC-side terminals of the two power units can then be connected with each other by an intermediate circuit choke. The AC-side of one power unit is connected with the power line, while the other power unit is connected with a motor. The power units of a DC voltage intermediate circuit converter can be configured as a compact power assembly instead of a DC intermediate circuit converter.
German Pat. No. DE 198 45 821 A1 describes a modular converter unit, in particular for use in rail cars. This converter unit includes a frame-like or dome-shaped metal housing, such as a housing frame, suitable to house the employed components. A cooling unit is provided on both sides of the housing frame and an intermediate circuit capacitor is provided centrally in the housing frame. IGBT modules are mounted on both sides of the housing frame. A rail system with connecting elements is arranged above the housing frame and electrically connects the terminals of the intermediate circuit capacitor with DC terminals of the IGBT modules. Isolation elements are provided in the region of the contact points between the rail system and the intermediate circuit capacitor. The intermediate circuit capacitor is conventionally mounted on the baseplate in the housing frame. AC terminals of the converter unit are routed to a terminal strip and connected by insulated standoffs with the cooling units and the housing frame. The current rails which preferably consist of wide insulated copper bands are secured to the IGBT outputs, the AC terminals and the insulated standoffs. The current rails terminate on one side, preferably below the housing frame, so that all components are accessible from one side, which allows easy and rapid assembly and disassembly of the converter unit. Openings in the housing frame that are oriented sideways and upwards are covered by a cover plate of the intermediate circuit capacitor and by the cooling units which have circumferential seals. The other opposite sides of the housing frame each have two openings that correspond to the cooling units secured in the housing frame, which also have circumferential seals. The rail system, which is constructed of electrically isolated foil-like conductors stacked one on top of the other, is screwed to the terminals of the intermediate circuit capacitor via the contact points located on the top side of the rail system and with the DC terminals of the IGBT modules via angled lateral straps. The unit in different mounting positions on support rails arranged on the housing frame. The converter unit can be mounted in a container using these mounting rails. The converter unit can be designed for water cooling and air cooling. If air cooling is employed, the cooling surface is formed by cooling fans in a conventional manner. If water cooling is employed, then conventional water connections for supply and discharge of the cooling water are provided, with the fitting arranged on the same side as the terminal strip. This configuration of the converter unit makes the unit compact; the unit can be used, for example, as a phase module in inverters, as a four-quadrant-control element and/or as a brake actuator and arranged in different combinations. The modular construction allows expansion of the basic configuration to cover different switching and power ranges, whereby different cooling systems can be used. This configuration of the converter unit has slightly less weight and volume.
It would therefore be desirable to provide a low-cost modular converter unit which employs a uniform device design, has identical interfaces and employs standardized switching techniques over its entire power range.